Caster



' spindle or stock.

UNITED STATES PATENT OFFICE@ WILLIAM ALFRED PEARN, OF LONGSIGHT, MANCHESTER, COUNTY OE LAN- y CASTER, ENGLAND.

SCREW-TAP CHUCK.

SPECIFICATION forming part of Letters Patent No. 357,025'I dated February 1,'887.

Application tiled September 10, 1586. Seria1 No.213.236. (No model.)

To all whom, it may concern/ Be it known that I, WILLIAM ALFRED PEARN, a citizen of Great Britain, residing at Longsight, Manchester, in the county of Lancaster and Kingdom of Great Britain,engineer, have invented certain new and useful Improvementsin orApplicable to Mechanism for Screw- Tapping; andI do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or iigures of reference marked thereon, which form a part of this specification.

Referring to the accompanying drawings, Figure l is an elevation of -my improved tap Fig. 2 is a top plan view thereof. Eig. 3 is a vertical Yaxial section of the same, shown partly in elevation. Fig. 4 is a like view of the spindle or stock, showing the Inode of attaching the tap thereto. Figs.

'5 and 6 are sections taken on lines l l and 2 2,

respectively, of Fig. 4f.

The object of my invention is to provide means for tapping screw-holes adapted for use either in the ordinary screwftapping machines or as an attachment to drilling-machines of that class in which the rotation of the -drillstock is reversible-such, for instance, as radial drills or other drilling-machines of this class.

The invention consists, essentially, in the peculiar construction of the device and inthe combination and cooperation of its several parts, substantially as hereinafter fully described, and as s et forth in the claims.

My` improved tap spindle or stock is composed of two sections, A and B. The section A of the tap-stock is made hollow nearly throughout its length and terminatesin a shank, A', by means of which it is connected or attached to the drill-stock of a drilling-ma chine in any usual or preferred manner, or to the tap-stock of a tapping-machine. Near its lower end the section A has a peripheral seat, a, formed by an annular ilange, a3, at the end of said section, and by vertical ribs or feathers ai, formed on the periphery of said section A. On the seat a of section A is loosely mounted 4a coupling-ring, R, provided with vertical grooves in its inner periphery for the reception of the ribs sai, so that the ring may be. slipped over section A to its seat. By means of this ring R the section A is coupled or connected to the section B, the ring R being screw- 5 5 threaded on its periphery and screwed into a correspondingly-threaded seat, b, formed in the lower section, B, of the drill-stock. As shown, the upper end of the lower section, B, of the drill-stock is provided with a 6o suitable recess to accommodate the lower end of section A.

It will be observed that by the described means of connecting the two sections of the drill-stock the upper section, A, is rotatable in the lower section, B,1but is held against independent endwise motion by the ring R, as it is obvious that when the ring is slipped over the upper section,A, andr screwed to its seat and said section. A is rotated, so that the 7a grooves in the ring will not register with the ribs a2, said ring will lock the sections together.

The upper end of section B has a flange,'B, in which are formed recesses b', Fig. 1, the 75 end walls of which are inclined, and on said flange is seated a corresponding flange, C', formed on the lower end of a sleeve or collar, @which flange is provided with projections c', seated in the recesses b of iiange B. The 8o sleeve or collar C is connected with the section A so as to permit it to move vertically thereon and rotate therewith. To these ends the section Ais provided with longitudinal feathers or ribs a2, above referred to, and the collar with grooves c2, for the reception of said rib 1 a2, as shown in Fig. 5.

The section A, near its upper end, is screwthreaded for the reception of a nut, N, and R is a recessed ring or collar loose on section 9o A below the nut N, said collar serving as an abutment for one end of a coiled spring, S, (mounted on section A,) whose other end bears upon the angeC of the sleeveV or collar C, whereby the latter is irmlyheld to its seat on flange B. of section B.

It will be observed that by means'of the described arrangement of devices the section A is so connected with the section B as to rotate the latter when vsaid section A is rotated by Ico the drill-stock in either direction, but should the section B meet with undue resistance in its rotation, the said resistance will arrest the movement of the section B, while section A will continue to rotate, the connection between the two being a yielding one. In other words, should the resistance to the rotation of section B become sufficiently great to endanger the operative devices of the drill or tapping niaehinc, the projections c o`n the flange C' will move out of the recesses b in iiange B of section B, the spring S yielding to said resistance and allowing the sleeve C to slide vertically on section A. The sleeve O will thus be disengaged from the ilange B, and, since both sec tions are rotatably connected together by means of the ring R, the section A will con tinue its rotation, while the section B will remain stationary. Of course it will be understood that the projections c may be formed on the flange B of section B and the recesses b in the iiange G of sleeve G, and the same results produced.

E is'a square spindle, to one end of which is secured a collar er nut, N', that serves as an abutment for one end of a coiled spring, S', on spindle E, the other end of said spring bearing on the inner face of the recess in the upper part of section B. The lower portion of sec tion B is provided with a socket, B, in which seats the screw-tap T. In the wall b2, that separates the recess and socket B1, is formed square opening, b, through which passes the spindle E, and by which it is held against rotation, said spindle being provided with an annular ilange or collar, c, that bears against the under side of the said partition-wall b".

The lower end of the spindle E--that is to say, that portion below the flange @mis screwthreaded, and is screwed into the screw tap or die T, which is held against rotation in the section B of the tap-stock by a groove, d, and feather or rib b, formed in the tap and on section B, respectively, as shown in Fig. G.

It will be seen that the tap or die T can be 'drawn out of the tap-stock against the stress of the spring S', for purposes presently eX- plained.

To secure the tap T to the spindle E the latter is drawn out of the tap-stock A B, and a fork, F, Fig. 4, is passed between the collar e of spindle E and the end of the section B, when said tap may be readily screwed to the spindle E, after which the fork is withdrawn, the spring S drawing the tap into its socket or seat. The nuts N and N also serve the purpose of adjusting the. tension of the springs S and S, respectively, as will be readily understood.

To use my improved tap-stockin a drillingmachine of the class described or in a tappingmachine, it is secured to the drill-stock, and t-he latter is lowered to bring the screw-tap to the hole in which a screwthread is to be cut. The drill-stock is then rotated until the tap has taken iirm hold of the metal, when the downward feed of t-he drill-stock may cease, since the tap is so connected with the tap-stock as to allow said tap to move out ot the stock or spindle as it penetrates into the hole to be threaded.

The vertical feed of the tap is an automatic one, as above described, the tap T moving vertically out of the stock when sufficient resistance is encountered to overcome the stress of the spring S on spindle E, to which the tap is screwed. XVhen the tap has reached the bottom of the hole to be threaded, or when Said tap has penetrated into the liole sufficiently far to bring its tlaring shoulder t in contact with the object tapped, the resistance to the rotation of the tap will be suiliciently great to overcome the stress of the spring S, and thereby disengage the ilanges B C', as above described, when the drill-stock will continue its rotation, while the tap-stoclr remains stationary. The operator then reverses the motion ot' the drill and tap stock to remove the tap from the threaded hole, the spring S assisting in this, and before the tap has moved clear out of the hole the operator moves the drill-stock up a little, so that as soon as the tap clears the hole the spring S will draw it up to its seat. The shock result-ing from the sudden impact of the tap on its seat under the stress of its spring S clears the said tap of the metal particles which may adhere thereto after leaving the threaded hole, and said tap is ready for threading the next hole.

It will be seen that by means of the construction described the operator is not only made aware of the fact that the tap has reached the limit of its operative movement, but he is also relieved of the operation of feeding the tap as it cuts the thread and of cleaning the tap after the thread is cut.

I am aware that it is not broadly new to construct drill-stocks (adapted to hold a tap) in two sections and gearing the two sections in such manner that when the lower or tap carrier section meets with inordinate resistance in its rotation said section will be thrown out of gear with the driving power on the upper section and remain stationary while said section continues to rotate.

Having now described my invention,what I desire to claim is- 1. The herein-described tapstock,consisting of the section A, provided near its lower end with the peripheral seat ct, and the section B, provided in its upperend with ascrew-threaded seat, and the coupling-ring R, whereby said sections are rotatably coupled together, substantially as and for the purpose specified.

2. The herein-described tap-spindle,consist ing of the sectionsA B, rotatably connected together, said section B being provided with an annular ilange, B, having recesses b', in combination with the sleeve C, having annular flange C', provided with recesses c', and the spring S, substantially as and for the purpose specified.

3. The combination,with a tap'stock having a socket for the reception of the tap, a yield IOO IIO

ing connection for said tap to allow end motion thereof within the socket, and a lock to lock said tap against independent rotation in its socket, substantially as and for the purpose 5 specified.

4. `The hereindescribed tap stock, composed of two sections rotatably connected together and a yielding locking device to lock the sections for joint rotation, one of said sec- Io tions being provided with a socket or seat for the tap, in combination with a yielding connection for said tap to allow end 4motion thereof within its seat, and a locking device to lock the tap to the spindle-section for `joint 15 rotation therewith, substantially as described,

for the purpose specified.

5. The combination, with the sections A B of the tap-stocl,constructed and connected together as described, of the spindle or rod E,

WILLIAM ALFRED PEARN. i

- Witnesses:

Y PETER J. LrvsEY,

WILLIAM FAULKNER. 

